Method of alloying reactive metals with aluminum or beryllium



METHOD OF ALLOYING REACTIVE METALS WITH ALUMINUM OR BERYLLIUM Oliver J.C. Runnalls, Deep River, Ontario, Canada, as-

signor, by mesne assignments, to the United States of America asrepresented by the United States Atomic Energy Commission No Drawing.Application October 18, 1954, Serial No. 463,047

SClaims. c1. 7s-122.1 V

active metals neptunium, cerium and/or americium and to provide a methodwhereby compounds of these metals may be simultaneously reduced andalloyed with alumi-. num or beryllium;

It has been found that aluminum and beryllium each act as a reducingagent for halides of the reactive metals, producing a volatile halidewhich is readily removed from the alloy formed during the reducingreaction.

In accordance with the invention a halide of one or more of the reactivemetals, neptunium, cerium and americium is mixed with aluminum orberyllium. The mass is heated at 700 to 1200 C., while maintaining asubstantial vacuum of about 10- mm. of mercury or better, until thehalide of the reactive metal is reduced and the metal itself alloys withthe reducing metal. Although the halides of these reactive metals aremore stable, thermodynamically, than the halides of aluminum andberyllium the reducing reaction proceeds efliciently due to thevolatilization of the halides of the reducing metal, aluminum 7 orberyllium.

The following examples illustrate the method.

(1) In preparing a neptunium-aluminum alloy containing 75% by weight ofneptunium, 54 parts by weight of neptunium fluoride were mixed with 32.6parts of aluminum powder. The mixture was heated under vacuum in aberyllium oxide crucible for two hours at 900 C. to reduce the neptuniumfluoride and alloy the metal with the aluminum according to the reactionMost of the aluminum fluoride product sublimed during the first halfhour of heating. 95% of the original neptunium appeared in thefluoride-free alloy. The amount of aluminum used may be varied asrequired by the alloy desired.

The aluminum halides produced in this reduction of the reactive metalhalides are a mixture of the monovalent and trivalent forms. Themonovalent halide predominates in the gaseous sublimate at the lowerreducing temperatures. Since the aluminum monohalides are appreciablymore volatile than the trihalides, the preferred heating temperature isin the region where the monohalide predominates 'in'the etfluent. Thereduction and alloying method is further illustrated by the reactionCeFa+xAl- CeAl(=-s)+3AlF. Upon condensation the United States Patent Thealloy, 60.5 parts by weight was loosely sintered and crystalline and wasreadily removed from the crucible. The chemical yield for the reactionwas about 97%.

A significant advantage of the method resides in the fact that thehalogenated reducing agent, aluminum or beryllium, is capable of beingremoved from the alloy formed by mere distillation leaving no compounds.Since aluminum monofluoride disproportionates on condensation two-thirdsof the aluminum is recoverable as metal.

The alloy may be heated at a temperature at which the reducing metaldistills to produce the reactive metal. When the alloy of Examples 1 and2 were heated in vacuum at a temperature in excess of 1250 C. thealuminum or beryllium was distilled 01f freeing the neptunium. Thisaflords a method of recovering the reactive metal from its halide,although more expensive than other reducing methods.

I claim:

1. A method of alloying reactive metal from the group consisting ofneptunium, cerium and americium with one of a group of reducing metalsconsisting of aluminum and beryllium which comprises mixing ahalide ofthe reactive metal with the reducing metal, heating the mass at 700 to1200 C. in vacuum to reduce said halide and form an alloy whiledistilling ofl the halide of the reducing metal formed during thereaction.

2. The method defined in claim 1 wherein the distilled halide iscondensed to recover reducing metal therein.

3. A method of making a neptunium-aluminum alloy which comprisesmixingneptunium fluoride with aluminum, heating the mixture under vacuumat about 900 C. to reduce the fluoride and form an alloy while sublimingofi the aluminum fluoride formed.

4. The method defined in claim 3 wherein the distilled aluminum fluorideis condensed to recover two-thirds of the aluminum metal for reuse.

5. A method of making a neptunium-beryllium alloy which comprises mixingneptunium fluoride with finely divided beryllium metal, heating themixture under vacuum at 1100-1200 C. to reduce the neptunium fluorideand form an alloy while distilling the beryllium fluoride formed.

References Cited in the file of this patent UNITED STATES PATENTS2,586,134 Winter Feb. 19, 1952 2,604,394 Emley' July 22, 1952 2,607,674Winter Aug. 19, 1952 2,678,267 Saunders May 1 1, 1954 FOREIGN PATENTS489,155 France Aug. 31, 1918 627,286 Great Britain Aug. 5, 1949

1. A METHOD OF ALLLOYING REACTIVE METAL FROM GROUP CONSISTING OFNEPTUNIUM,CERIUM AND AMERICIUM WITH ONE OF A GROUP OF REDUCING METALSCONSISTING OF ALUMINUM AND BERYLLIUM WHICH COMPRISES MIXING A HALIDE OFTHE REACTIVE METAL WITH THE REDUCING METAL, HEATING THE MASS AT 700 TO1200*C. IN VACUUM TO REDUCE SAID HALIDE AND FORM AN ALLOY WHILEDISTILLING OFF THE HALIDE OF THE REDUCING METAL FORMED DURING THEREACTION.